Ever since 2010, Rob Zombie has been on a schedule of releasing new music once every three years. That schedule may or may not be broken in 2018, as Zombie has announced he's working on the followup to 2016's The Electric Warlock Acid Witch Satanic Orgy Celebration Dispenser right now!
His first Instagram post announces he's working on new music, while the second post says he's in the studio. So it's not entirely clear if he's recording the new material right now, or just holed up in the studio knocking out some demos.
Either way, new Rob Zombie 2018 (probably).